Humanure: Waste or Resource?

CAUTION: I use many different words in this post to refer to human feces, most of which just make my four-year-old son laugh (OK.. me too), but some of which are slang and might be considered offensive by some. You have been warned.

The Humanure Handbook quickly and easily catapulted itself to one of my favorite books of all time. The plot is pretty simple. The human turd has been looked down on for much of Western history as a villain, a bearer of death and disease and something to be got rid of as quickly and cleanly as possible (at least for those of us who don’t work in wastewater management). But wait… Could it be that this much maligned malefactor is really only a misunderstood and much underutilized natural resource in disguise? It turns out that while there are lots of plot twists (pathogens, night soil, etc.), the reprobate pile of human excrement is actually a very smelly Boy Scout waiting to waltz with thermophilic microbial lifeforms until he turns your dung into the most delicious and nutritious tomatoes you’ve ever eaten. Only the topics of poop or compost can inspire me to wax so poetic. The Humanure Handbook combines both in a glorious tome destined to inspire generations to come and probably save the planet.

Stop Pooping in the Water Cooler

The world is divided into two categories of people: those who shit in their drinking water supplies and those who don’t. We in the western world are in the former class (15).

This seems to be the motto and rallying cry of the book. Author Joseph Jenkins reminds us that “Less than one percent of the Earth’s water is available as drinking water. Why shit in it?” (117). This is really what happens when we use modern, western toilets. We pull that innocent-looking handle and wave goodbye to our waste as gallons of water swirl around carrying our excrement off to unforeseen lands that we then promptly ignore. The truth is that the water in our waste systems is for no other purpose than carrying away our waste. If it weren’t for us using it to get rid of our excrement, then it would be perfectly acceptable water for our own consumption.

People around the world are trying to keep feces and contaminants out of what water supply they have, while we abuse our abundance by happily turning our water into an environmental hazard that is ridiculously expensive to dispose of properly, if indeed, it is even possible. In a world where “one out of four people in developing countries still lack clean water, and two out of three lack adequate sanitation” (Source: State of the World 1999, p. 137), it’s at least silly, if not criminal, for us to be using our own water resources this way.

Jenkins covers thoroughly all the systems used to dispose of our ordure (outhouses, septic systems, wastewater treatment, stabilization ponds, constructed wetlands and composting toilet systems), the structure and problems associated with them including handling of pathogens and toxins. In the end his beloved system of managed thermophilic compost (which is a fancy way of saying composting toilet systems) comes out smelling like roses, quite literally if that’s what you want to grow with it.

Wasting Away

The problem, however, is not just in the facts, which add up considerably in favor of humanure. The problem is really our understanding of what is waste. Jenkins points out that Asian countries did not develop western wastewater treatment systems and have used “night soil” (raw humanure) for millenia on agricultural lands. (He does point out that while this returns nutrients to the soil and destroys many of the pathogens through decomposition it can also be a vector for disease because the humanure is not composted.) They don’t even have swear words that refer to human excrement in many Asian languages, because it could never be an insult to call someone something so valuable. Think about that next time the hammer hits your thumb instead of the nail!

It’s a common semantic error to say that waste is, can be or should be recycled. Resource materials are recycled, but waste is never recycled. That’s why it’s called “waste.” Waste is any material that is discarded and has no further use… “Human waste” is a term that has traditionally been used to refer to human excrements, particularly fecal material and urine, which are by-products of the human digestive system… Humanure, unlike human waste, is not waste at all – it is an organic resource rich in soil nutrients. Humanure originated from the soil and can be quite readily returned to the soil, especially if converted to humus through the composting process (7-8).

The challenge is a radical shift in our thinking, not just a matter of where or in what we put the end product of our digestive system. We have come to assume that certain things are “waste” and must be disposed of through expensive and dangerous chemical processes or storage. His comparison of “sanitary” landfills (which use waterproof liners carefully folded up around the edges) to gigantic disposable diapers really stuck with me.

We’ve done such a good job at removing our own waste from sight and therefore our awareness, that we can hardly fathom that we, North Americans, produce 1,000 pounds of humanure in a year and another 1,000 pounds of solid waste. That’s one ton of waste per person every year, half of which can be turned into an agricultural resource (12).

Jenkins also does a thorough job describing exactly how to create an agricultural resource from your own droppings. There are plans for many different permutations of sawdust toilets you can build yourself, in addition to diagrams of many of the commercial products and composting toilets that are out there. There is also a design for the Humanure Hacienda which is two compost bins with a covered third bin that collects rainwater.

The problem of waste that’s created by our consumption, both through the food we eat and the stuff we buy, must be dealt with in more sustainable ways. One of the best things we can do is turn our own waste into a resource.